81 Speedometer Calibration
Thread Starter
Racer
Joined: Sep 2015
Posts: 393
Likes: 21
From: Centreville, Maryland
81 Speedometer Calibration
Well, I am either REALLY bad at searching for things on here or no one has ever started a thread on any topic that I have ever started lol. Just curious as to how I can fix my speedo. It is off by about 5MPH. Not a huge deal, but I would definitely like to correct it so it reads properly. Is there an easy way to do this or are there any good places that I can send it to that wont cost me an arm and a leg? Thanks in advance everyone.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
You could make a change in the driven gear at the tranny, 1 tooth is usually 5 mph on the speedo. Then there is also the possibility someone put the wrong gear in the car or the tire size has been changed, or something else.... So for starters I'd just pull the gear out and see what color it is..... then make a change.
The speedometer itself can also be calibrated but you'd need to remove it, have a calibration machine, and in your case you have to remove the odometer from the head to gain access to the tension spring (calibration arm) retainer. If it were me, I'd just try to make a change in the driven gear for a temp fix. If you know the tire sizes are correct and if you have the tranny, (at or 4sp) you can look up the factory gears on my tech site.
The speedometer itself can also be calibrated but you'd need to remove it, have a calibration machine, and in your case you have to remove the odometer from the head to gain access to the tension spring (calibration arm) retainer. If it were me, I'd just try to make a change in the driven gear for a temp fix. If you know the tire sizes are correct and if you have the tranny, (at or 4sp) you can look up the factory gears on my tech site.
Thread Starter
Racer
Joined: Sep 2015
Posts: 393
Likes: 21
From: Centreville, Maryland
Thanks for the info! All of the tires are correct size and I havent been able to look at the gear on the tranny but it just confuses me that it is roughly correct up to about 30 mph. then its off by 5 or so the rest of the way.
Former Vendor
Joined: Aug 2006
Posts: 76,656
Likes: 1,853
From: Jeffersonville Indiana 812-288-7103
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15
Willcox
